Electric machine with combined axial- and radial-flux

Abstract

An axial-flux and radial-flux motor including a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a shaft. A stator assembly having a core with a non-ferromagnetic material and including a first axial-flux stator yoke with an inner wall rigidly attached on an outer surface of a first edge wall of the core. A second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the core. The first and the second axial-flux stator yokes each include an outer wall with slots. A radial-flux stator yoke with slots includes an inner wall rigidly attached on a continuous outer wall of the core. The radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets. Windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke.

What is claimed is: 
     
       1. An electrical machine that is an axial-flux and radial-flux motor, comprising:
 a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a shaft; and 
 a stator assembly having a stator core with a non-ferromagnetic material and including
 a first axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a first edge wall of the stator core, and a second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the stator core, wherein the first and the second axial-flux stator yokes each include an outer wall with slots; 
 a radial-flux stator yoke with slots includes a continuous inner wall rigidly attached on a continuous outer wall of the stator core, wherein the radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets; and 
 windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke. 
 
 
     
     
       2. The electric machine of  claim 1 , wherein the stator assembly is rigidly attached to the shaft, and wherein the first and the second axial-flux stator yokes have slots in an axial direction, the radial-flux stator yoke has slots located on an outer diameter surface of the continuous outer wall of the stator core, and the windings include a set of toroid-shaped multiphase windings configured within the slots of the first and second axial-flux stator yokes and the radial-flux stator yoke. 
     
     
       3. The electrical machine of  claim 1 , further comprising:
 a two axial-flux rotor assembly rotatively attached to the shaft via bearings, and engages with the first and the second axial-flux stator yokes, each axial-flux rotor assembly having an axial-flux rotor housing rigidly attached to an outer race of bearings, an axial-flux rotor back-iron attached to the axial-flux rotor housing, and an axial-flux permanent magnet array attached to the axial-flux rotor back-iron. 
 
     
     
       4. The electrical machine of  claim 3 , further comprising:
 a radial-flux rotor assembly rigidly connected to an axial-flux rotor housing, and rotatively engaged with the radial-flux stator yoke, 
 wherein the radial-flux rotor assembly includes a radial-flux rotor housing rigidly attached to the axial-flux rotor housing, a radial-flux rotor back-iron attached to the radial-flux rotor housing, and a radial-flux permanent magnet array attached to the axial-flux rotor back-iron. 
 
     
     
       5. The electrical machine of  claim 4 , wherein the axial-flux permanent magnet arrays of the two axial-flux rotor assembly and the radial-flux permanent magnet array each have alternative polarity. 
     
     
       6. The electrical machine of  claim 4 , wherein the first and second axial-flux stator yokes and the axial-flux rotor back-irons of the two axial-flux rotor assembly are made of spiral-shaped electrical lamination, or that the radial-flux stator yoke and radial-flux rotor back-iron are made of stacked electrical lamination. 
     
     
       7. The electrical machine to  claim 1 , wherein the non-ferromagnetic material of the stator core includes at least 90% of one or more non-ferromagnetic materials. 
     
     
       8. The electrical machine of  claim 1 , wherein the non-ferromagnetic material of the stator core is a material that is one of plastic, carbon fiber reinforced polymer, fiberglass or an iron (ferrous) free material. 
     
     
       9. The electrical machine of  claim 1 , wherein the non-ferromagnetic material of the stator core includes a level of an electrically conductive material and a level of mechanical stiffness associated with one of titanium, fiber glass or acetal homopolymer. 
     
     
       10. The electrical machine of  claim 1 , wherein the non-ferromagnetic material of the stator core is a material that is one or more non-ferromagnetic metals obtained from sulfide, carbonate or silicate minerals, and is non-magnetic. 
     
     
       11. The electrical machine of  claim 1 , wherein the windings are wrapped around the assembled stator yoke and include a winding pattern having end turns which are termed toroidal windings, such that the toroidal windings reduces an amount of a length of the end turns, resulting in an increase in an amount of overall efficiency of the electrical machine, when compared with a similarly configured electric machine without the toroidal windings. 
     
     
       12. The electrical machine to  claim 1 , wherein the windings include a copper material and are wrapped around the assembled stator yoke that include a winding pattern with end turns that are termed toroidal windings, such that the toroidal windings reduces an amount of a length of the end turns, resulting in a total amount of a motor's windings copper loss which improves a motor's overall efficiency. 
     
     
       13. The electrical machine of  claim 1 , wherein the windings are thermally connected to the shaft, such that the thermal connection of the windings and the shaft is implemented using a thermally conductive and electrically insulating material of epoxy. 
     
     
       14. The electrical machine of  claim 1 , further comprising:
 bearings are utilized so the rotor is rotatively attached to the shaft, such that the shaft is a hollow stationary shaft, and 
 wherein the stator core and the shaft include a coupling feature adapted to selectively couple and mate the stator core to the shaft, so that the stator assembly is fixed to the shaft in order to transmit a torque action and maintain an angular correspondence, to produce a torque force. 
 
     
     
       15. An electrical machine that is an axial-flux and radial-flux motor, comprising:
 a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a stationary shaft; and 
 a stator assembly including
 a stator core with a non-ferromagnetic material, the stator core including a first edge wall, a second edge wall and a continuous outer wall circumferentially positioned around the stator core; 
 a first axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a first edge wall of the stator core, and a second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the stator core, wherein the first and the second axial-flux stator yokes each include an outer wall with slots; 
 a radial-flux stator yoke with slots includes a continuous inner wall rigidly attached on a continuous outer wall of the stator core, wherein the radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets; and 
 windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke, wherein the stator assembly is fixed to the stationary shaft of which the rotor rotates around the same stationary shaft, in order to transmit a torque action to produce a torque force. 
 
 
     
     
       16. The electrical machine of  claim 15 , wherein the radial-flux stator yoke includes stacked laminations of sheets that are electrically laminated and insulated from each other, such that sheets have substantially a same shape, and are stacked one on top of another in an axial direction or connected to one another. 
     
     
       17. The electrical machine of  claim 15 , wherein the first and second axial-flux stator yokes includes stacked laminations of sheets that are electrically laminated and insulated from each other, the stacked laminations of sheets are axisymmetric relative to a radial straight line, wherein the laminations for the first and second axial-flux stator yokes include the sheets stacked one on top of another in a radial direction or connected to one another. 
     
     
       18. The electrical machine of  claim 15 , wherein the radial-flux stator yoke is ring-shaped and includes an includes an inner facing surface of a continuous inner wall rigidly attached on an outer facing surface of the continuous outer wall of the non-ferromagnetic core. 
     
     
       19. The electrical machine of  claim 15 , wherein the windings are wrapped around the assembled stator yoke to include multiple loops of magnetic copper wires and have three-phases along with a pole pair number. 
     
     
       20. An electrical machine that is an axial-flux and radial-flux motor, comprising:
 a rotor mounted rotatably about a machine axis; 
 a stator assembly including
 a fixed non-ferromagnetic stator core attached to the shaft; 
 a first axial-flux stator yoke and a second axial-flux stator yoke both having slots in an axial direction; 
 a radial-flux stator yoke with slots is positioned on an outer diameter surface of the fixed non-ferromagnetic stator core, and a set of toroid-shaped multiphase winding configured within the slots of the first and the second axial-flux stator yokes the radial-flux stator yoke;
 two axial-flux rotor assemblies rotatively attached to the shaft, and engage with the first and the second axial-flux stator yokes, each axial-flux rotor assembly includes an axial-flux rotor housing rigidly attached to an outer race of bearings, an axial-flux rotor back-iron attached to the axial-flux rotor housing, and an axial-flux permanent magnet array attached to the axial-flux rotor back-iron; and 
 
 a radial-flux rotor assembly rigidly connected to both axial-flux rotor housings, and rotatively engaged with a radial-flux stator yoke, the radial-flux rotor assembly has a radial-flux rotor housing rigidly attached to the both axial-flux rotor housings, a radial-flux rotor back-iron attached to the radial-flux rotor housing, and a radial-flux permanent magnet array attached to the both axial-flux rotor back-irons. 
 
 
     
     
       21. The electrical machine of  claim 20 , wherein a pole pair number of the permanent magnet arrays matches with a pole-pair number of the stator winding to form a synchronous surface mount permanent magnet motor, or the pole pair number of the permanent magnet arrays matches with the stator slot number plus or minus the stator winding pole-pair number to form a vernier permanent magnet motor. 
     
     
       22. A system comprising:
 a transceiver to receive signals from sensors associated with an axial-flux and radial-flux (AFARF) motor; 
 a digital controller configured to receive the signals, and generate control signals specifying values of one or combination of a multi-phase voltage or a current for the AFARF motor, for tracking a reference trajectory of torques of the AFARF motor, and wherein the AFARF motor has a load whose position is controlled by the AFARF motor and is controllable by the digital controller, such that the AFARF motor includes: 
 a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a shaft; and 
 a stator assembly having a stator core with a non-ferromagnetic material and including
 a first axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a first edge wall of the stator core, and a second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the stator core, wherein the first and the second axial-flux stator yokes each include an outer wall with slots; 
 a radial-flux stator yoke with slots includes a continuous inner wall rigidly attached on a continuous outer wall of the stator core, wherein the radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets; and 
 windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke that form a toroid-shaped stator assembly; and 
 
 an inverter in communication with the digital controller and the AFARF motor, is configured to supply the multi-phase voltage and the current generated according to the generated control signals to multi-phase windings of the AFARF motor to reduce an error between the reference trajectory and a measured torque of the AFARF motor, if the error is above a predetermined error threshold.